Marker system

ABSTRACT

A marker system for applying to surfaces of items, articles, goods, vehicles and/or premises, said marker system comprising: a marker comprising a temperature resilient medium having a predefined carbonisation temperature capable of securing the marker system onto a surface; wherein the medium contains an inorganic matrix having a predefined fusing point lower than the predefined carbonisation temperature of the medium; such that when the marker system is subjected to temperatures above the predefined carbonisation temperature of the medium, the inorganic matrix fuses to the marker to form an adhesive protective layer thereby securing the marker onto said surface. A composition comprising the marker system. An item, an article, a good, a vehicle and/or premises comprising a surface impregnated with the marker system.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 13/639,096 filed on Jan. 8, 2013 which issued as U.S. Pat. No. 8,962,337 onFeb. 24, 2015. U.S. application Ser. No. 13/639, 096 is the U.S.National Stage of International Application No. PCT/GB2012/050730, filedon Mar. 30, 2012, published in English. International Application No.PCT/GB2012/050730 claims priority to Great Britain Patent ApplicationNo. GB 1105373.3, filed Mar. 30, 2011, the entire teachings of the aboveapplications are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to an improved marker system for use inthe security and tracing of items, articles, goods, vehicles or persons.In particular, the invention described herein is directed towards animproved marker system capable of withstanding high temperatures.

BACKGROUND TO THE INVENTION

Generally, non-ferrous metals are expensive materials and their price issteadily increasing. As a result theft of such metal items is on theincline. Such metals, for example copper and aluminium are often used incabling, in rail networks and telecommunications. Accordingly, the theftof such metal items is particularly costly for the party suffering theloss, not only due to the high value of the materials involved but theensuing loss due to disruption of business and infrastructure can beorders of magnitude higher.

There is therefore a need to prevent or at least reduce the level ofsuch theft. A way of doing this is to provide a mark on the materialwhich establishes proof of ownership. In this way theft can beestablished and charges brought against those in possession of itemswhich could positively be identified as stolen.

In recent years, the use of marker systems has been particularly usefulin preventing crime and for tracking and identifying the authenticity ofitems. Such marker systems, as have been developed by the applicant formany years, have found particular application in the fields of securityand crime prevention/deterrence, for example as described in WO93/07233, GB 2369078, GB 2410208 and GB 2413675, amongst others.Analysis of the surface onto which the marker system is placed ordeployed can provide a reliable method of tracing or authenticatingitems, articles, goods, vehicles or persons.

An important feature of a marker system is its stability under varyingconditions. These conditions can involve excesses due to weather orchemical assault and deliberate attempts to remove the marker frommarked items. Additionally, where the stolen goods comprise metal ormetallic compounds, it is common that the items will be subjected toheat either to alter the shape or look of the goods or alternatively toremove any non-metallic material therefrom, such as for exampleinsulating material that surrounds cabling.

Copper and aluminium are used extensively in cabling due to theirelectrical and thermal properties. Aluminium melts at 660° C. and copperat 1084° C. At present, it is not possible to identify such metals asstolen if they have been subjected to very high temperatures in orderfor example to try and remove a security mark applied thereto. Anyindicator or security mark which is capable of identifying such metalitems would need to be able to function subsequent to the application ofsuch high temperatures. For example, when electrical cable is subjectedto high temperatures to burn off the insulation, the former occurs atquite a low relative temperature unlike the latter which can occur attemperatures over 1000° C.

Given that most metals which are stolen will be subjected to heat atvarious stages, a marker for use on metals must be capable ofwithstanding the type of temperatures to which the stolen metal might besubjected.

Therefore, there is a need for a marker system capable of withstandinghigh temperatures so that marker and consequently the goods remainidentifiable.

In a first aspect of the invention, there is provided a covert markersystem for applying to surfaces of items, articles, goods, vehiclesand/or premises, said marker system comprising: a marker comprising atemperature resilient medium having a predefined carbonisation ormelting temperature and capable of securing the marker system onto asurface; wherein the medium contains an inorganic matrix having apredefined fusing point lower than the predefined carbonisationtemperature of the medium; such that when the marker system is subjectedto temperatures above the predefined carbonisation temperature of themedium, the inorganic matrix fuses to the marker to form an adhesiveprotective layer thereby securing the marker onto said surface.

In one embodiment of the invention, the inorganic matrix is ground glassand preferably a finely ground glass. In one embodiment the glassconstitutes approximately 20% wt/wt of the matrix.

In one embodiment of the invention the organic medium present in theformulation is an aqueous acrylate emulsion and which advantageouslycomprises a material having a high inherent stability that is resistantto environmental conditions and/or removal through washing or abrasion.

In a preferred embodiment of the invention the marker comprises afingerprint and which is preferably an organometalic fingerprint.Preferably, the fingerprint comprises a unique identifying tracer.

In another preferred embodiment of the invention the marker furthercomprises an indicator which may, for example, be an inorganicindicator. Preferably, the indicator comprises at least onephosphorescent or fluorescent material capable of phosphorescing orfluorescing at particular wavelengths when subjected to a particularstimulus. Preferably, the indicator comprises at least one materialcapable of phosphorescing or fluorescing when subjected to an infraredor ultraviolet stimulus.

In accordance with the present invention, the matrix is such that it iscapable of preserving the integrity of the markers at high temperatures,preferably in excess of 1000° C.

In one embodiment of the invention, the marker system is provided in asprayable form.

An item, an article, a good, a vehicle and/or premises comprising asurface coated or otherwise impregnated with the marker system alsoforms part of the present invention.

The invention will now be further described with reference to thefollowing exemplary embodiment.

Matrix

The marker system includes a matrix and an aqueous polymer emulsion tobind a marker to the surfaces of items, articles, goods, vehicles and/orpremises. Advantageously, the polymer system, which is water based toavoid the use of solvents, initially acts as an adhesive to secure themarker or surface coating to the goods being protected. As the goods maybe subject to high temperatures, it is desirable for the matrix to beable to withstand high temperatures; failing which, the matrix may loseits adhesion to the surface, by for example carbonising, and the markersystem will simply fall off the surface, when the marker system issubjected, either directly or indirectly, to high temperatures. In orderto ensure that a stolen item is identifiable even where it has beensubjected to heat; it is desirable for the polymer emulsion and matrixcombination to secure the marker system across a wide range oftemperatures.

To determine a suitable composition to use as an inorganic matrix,various systems have been tested; particularly, systems based onsilicones and silanes were tested. These systems demonstrated theadvantage of not darkening when the marker system was subjected to heat.However, during testing, none of these systems maintained their adhesionto the substrate leaving the marker system free to just fall from themarked item.

In order for the matrix to be capable of securing the marker to asurface across a range of temperatures, i.e. to over 1000° C., thepresent application provides for an inorganic matrix, typically a glassas one of its components. When heat is applied to glass, the glasssoftens. As the glass softens, it becomes more fluid and sticky. Whenthe softened glass is subsequently cooled, the glass with reform into asolid and anything which was fused to it will be encapsulated in a glasslayer; for example, the marker and the surface of the item on which themarker system has been secured.

The present invention provides a matrix which comprises preferably acomposition of a glass in a medium. This composition of matrix was foundto be particularly effective in securing the marker to the surface whenthe surface was subjected to high temperatures. In one embodiment of theinvention, the medium is a polymer emulsion, i.e. an acrylate emulsion,which at low temperatures holds the glass powder in place. It is only athigher temperatures that the two roles are reversed.

A preferred composition of the matrix comprises a composition of groundglass in an organic medium. The carbonisation temperature of the organicmedium and the fusing point of the glass are known. In fact, the organicmedium and the glass may be selected from a range of compositions basedon the range desired. Particularly, the selection may be made such thatthe predefined fusing point of the glass is lower than the carbonisationtemperature of the medium.

One advantage of selecting a glass having a predefined fusing pointlower than the carbonisation temperature of the medium is that when theadhesive properties of the medium start to decrease, because thecarbonisation temperature of the medium is being approached or haspassed, the fusing point of the glass will also have passed such thatthe glass will stick to the marker as well as the surface. Thistherefore ensures that the marker is securely placed on the particularsurface across a range of temperatures.

Marker

The marker detailed above may further comprise a fingerprint and/or anindicator. It is preferable that each of the components of the marker isalso capable of withstanding or are resilient to high temperatures.

Fingerprint

The marker preferably comprises a unique fingerprint capable ofdistinguishing one marker system from that of another and to identifythe source of the item to which it is coupled. The fingerprint maycomprise a solvent medium containing a volatile component, together withfor example one or more trace materials which can be varied in such amanner as to produce unique formulations. The combinations of tracematerials may advantageously be varied by modelling the compositions on,for example, binary strings to produce large numbers of unique products.However, other suitable coding methodologies may also be utilised asappropriate. The term “trace materials” applies herein to materialswhich would not normally be present in the environment of use. The mostcommonly used trace materials are metal compounds.

Trace materials can advantageously therefore be combined in a way whichgives good evidential value to law enforcement agencies, as each uniqueformulation may be allocated to a particular premises, location orperson, and this information is stored in a central database which canbe accessed by a law enforcement agency receiving the report of alaboratory analyzing the mixtures which are to be discussed.

The trace materials may be assigned constant positions in a binarystring with their presence being given by a “1”, and their absence by a“0”. If, for example, one were to set a limit of thirty digits for thestring, one could begin with combinations of two trace materials, andgenerate all combinations containing any two trace materials. One couldthen go to groups of three trace materials, and generate allcombinations of any three trace materials. This could continue until thenumber of trace materials is equal to the number of digits in thestring.

With a thirty digit string, the total number of unique combinations oftrace materials is approximately one billion. However, it is possible toprepare an infinite number of mixtures having compositions based uponunique binary sequences, the composition of each being unique.

Binary strings are provided as exemplary of the manufacturing procedureswhich can be used. Octal strings may also be used. Decimal numbers andrandom number generation can be used to generate potential codes,although these will need to be checked and converted to binary or octalsequences prior to use.

The unique nature of each composition can be checked during QualityControl following manufacture. The composition can then be stored in adatabase, allocated to a premises, location, or person, and the sourceof goods located at a later time can be traced to the premises, locationor person via the composition.

Of course, the greater the number of trace materials used, the greaterthe certainty in identification later on, since the chance presence oftrace materials can be ruled out.

To determine the fingerprint which was best able to withstand the effectof high temperatures, several different types of fingerprint weretested. Organic materials were carbonised at relatively low temperaturesof less then 500° C.

In one embodiment of the invention, inorganic materials may be used asthe fingerprint. These materials have the best performance, of thematerials tested. However, the materials themselves were difficult towork with.

A preferred fingerprint for use in the invention is an organometallicmaterial. During testing, these compounds yielded the best results asthey were initially easy to work with and when subjected to hightemperature, the organic burnt off leaving the metals as fingerprint.

Indicator

The marker preferably comprises an indicator material, which can quicklyprovide a preliminary, gross indication of the presence of a compositionaccording to the invention. The indicator material can either be “overt”or “covert.” An overt material is typically one which can be seenunaided by technology, such as a dye or pigment. With an overtindicator, it is immediately evident from an observation of the articleor person that a mark has been provide thereon which may act as adeterrent. In one embodiment both a covert and overt mark may be appliedthus combining the deterrent effect of the overt mark with the covertproperties of the covert mark. For example, if the overt mark failed toact as a deterrent and the perpetrator tried to remove the overt mark;even if they were successful the stolen item could nevertheless still beidentified by virtue of the covert mark.

A covert indicator will remain hidden until some technical means orstimulus is used to make it obvious. Usually, a covert indicator willbecome visible upon application of a radiation source other than visiblelight, and of these, fluorescent indicators are most common. Thus, thecovert indicator will often be at least one fluorescent material whichis soluble in a solvent system, and which is easily detectable uponexamination with ultraviolet light, for example.

It is possible to utilise a fluorescent material which when exposed toUV light fluoresces in a particular colour, each particular fluorescentmaterial being selected for a particular customer, so that when thecomposition containing the selected fluorescent material is applied to asurface of articles or goods, then any unauthorised removal of sucharticles or goods can be linked back to the particular customer as thesource of goods. It is further possible to utilise a combination of twoor more fluorescent materials having differing A max emissionwavelengths.

It is possible to identify said two or more materials by utilising aUV-absorption spectrum or a fluorescent emission spectrum of anindicator. Accordingly, such combination of materials, when applied to asurface of articles or goods, can also be used to link the particulargoods to the customer. Alternatively or additionally, the indicator maycomprise at least one phosphorescent material capable of phosphorescingwhen subjected to stimulus.

The indicator is preferably utilised in spray form and can be combinedwith various solvent systems and surfactants. The indicator is suitablypresent in an amount of 0.1 to 40% by weight of the composition.

When the gross indicator means is fluorescent, the composition caninclude one or more of any suitable fluorescent materials.

In terms of suitable indicators, both organic and inorganic materialswere tested. Some organics, especially of the oxazinone functionalityperformed well, but did still degrade well below the requiredtemperature and lost their fluorescence.

A preferred compound for use in the invention as an indicator is aninorganic emitter. A range of inorganic emitters were tested and some ofthese did maintain a good fluorescent emission beyond 1000° C.

Marker System

Testing was performed for a marker system comprising an indicator, afingerprint, and a matrix of 20% finely ground glass in an organicmedium. The combination of these materials gave a marker that does stayoperational and fully functional at temperatures in excess of 1000° C.

In an embodiment of the invention, this marker system may be applied toan article. In a preferred embodiment, the marker system is colourless,odourless and has no feel thereto, and is therefore undetectable.

A number of embodiments have been described herein. However, it will beunderstood by persons skilled in the art that other variants andmodifications may be made without departing from the scope of theembodiments as defined in the claims appended hereto.

1. A method for applying a marker system to surfaces of items, articles,goods, vehicles and/or premises; wherein said marker system comprising:a marker comprising a temperature resilient medium having a predefinedcarbonisation temperature capable of securing the marker system onto asurface; wherein the medium contains an inorganic matrix having apredefined fusing point lower than the predefined carbonisationtemperature of the medium; the method comprising the steps of: (i)subjecting the marker system to temperatures above the predefinedcarbonisation temperature of the medium, and (ii) fusing the inorganicmatrix to the marker to form an adhesive protective layer therebysecuring the marker onto said surface.
 2. The method of claim 1, whereinthe adhesive layer substantially preserves the integrity of the marker.3. The method of claim 1, wherein the inorganic matrix is a groundglass.
 4. The method of claim 3, wherein the glass is a finely groundglass,
 5. The method of claim 3, wherein the glass constitutesapproximately 20% wt/wt of the marker.
 6. The method of claim 1, whereinthe medium is an organic medium.
 7. The method of claim 6, wherein themedium comprises an aqueous acrylate emulsion.
 8. The method of claim 1,wherein the medium comprises a material having a high inherent stabilitythat is resistant to environmental conditions and/or removal throughwashing or abrasion.
 9. The method of claim 1, wherein the markerfurther comprises a fingerprint.
 10. The method of claim 9, wherein thefingerprint is an organometalic fingerprint.
 11. (canceled)
 12. Themethod of claim 1, wherein the marker further comprises an indicator.13. The method of claim 12, wherein the indicator comprises an inorganicindicator.
 14. The method of claim 12, wherein the indicator comprisesat least one material capable of phosphorescing when subjected tostimulus.
 15. The method of claim 12, wherein the indicator comprises atleast one material capable of emitting visible or near infra redradiation at a specific frequency when subjected to infrared stimulus.16. The method of claim 12, wherein the indicator comprises at least onematerial capable of emitting visible or near infra red radiation whensubjected to ultra-violet stimulus.
 17. The method of claim 1, whereinthe surfaces of items, articles, goods, vehicles and/or premisescomprise metal surfaces.
 18. The method of claim 1, wherein the matrixis capable of preserving the integrity of the markers at hightemperatures.
 19. The method of claim 18, wherein the high temperaturesinclude temperatures in excess of 1000° C.
 20. (canceled)
 21. The methodof claim 1, wherein said marker system is applied to said surface byspraying.
 22. (canceled)
 23. The method of claim 1, further comprising astep of impregnating said surfaces with the marker system beforesubjecting the marker system to temperatures above the predefinedcarbonisation temperature of said medium.